After my first "bad" experience with a full custom, I think first and foremost I'd look for a maker with a good name/reputation.
next would be the steel, 5160, 154CM, INFI, D2; so many good ones but it's really the heat treat that makes it special, so
other buyers experience would really be favorable.
Though popular I'm not one for clip points, give me spear point or drop point, even sheeps foot work for me.
I like full flat grinds because their easy to maintain and good for slicing and a general use edge.
Natural scales are beautiful but I'm more of a user so man-made materials is the way I'd go.